Prevention and detection of overheating from component short circuits

Abstract

A personal electronic device can include a main printed circuit board having disposed thereon a processing unit, one or more auxiliary circuits coupled to the main printed circuit board by one or more corresponding flexible printed circuits and one or more temperature sensors disposed on one of the flexible printed circuits. A processing unit of the portable electronic device can be configured to monitor the one or more temperature sensors, provide a warning in response to a monitored temperature exceeding a first threshold, and to cause a shutdown of at least a portion of the personal electronic device in response to the monitored temperature exceeding a second threshold. The temperature sensors can be negative temperature coefficient resistors.

The invention claimed is: 
     
       1. A personal electronic device comprising:
 a battery; 
 a regulator coupled to the battery and configured to power a plurality of loads; and 
 one or more management circuits configured to operate the regulator to power the plurality of loads and to monitor the battery; 
 wherein at least one of the one or more management circuits is configured to monitor at least one of a current or power supplied by the battery to the regulator or at least one of a current or power supplied by the battery to the plurality of loads and to compare the monitored current or power to an expected current or power draw corresponding to an operating state of the personal electronic device to detect an electrical fault with a component of the personal electronic device. 
 
     
     
       2. The personal electronic device of  claim 1  wherein the at least one of the one or more management circuits is configured to monitor at least one of a current or power supplied by the battery over time so as to monitor charge or power consumption. 
     
     
       3. The personal electronic device of  claim 2  wherein the at least one of the one or more management circuits is integrated with the regulator. 
     
     
       4. The personal electronic device of  claim 2  wherein at least two of the plurality of loads are powered by a common bus from the regulator. 
     
     
       5. The personal electronic device of  claim 2  wherein the at least one of the one or more management circuits is configured to detect an electrical fault with a component of the personal electronic device by:
 providing a warning in response to the monitored current or power exceeding the expected current or power draw corresponding to the operating state of the personal electronic device by a first threshold; and 
 causing a shutdown of at least a portion of the personal electronic device in response to the monitored current or power exceeding the expected current or power draw corresponding to the operating state of the personal electronic device by a second threshold. 
 
     
     
       6. The personal electronic device of  claim 5  wherein the processing unit is configured to provide a warning in response to the monitored current or power exceeding the expected current or power draw corresponding to the operating state of the personal electronic device by a first threshold by:
 logging an overtemperature warning in a memory of the personal electronic device; and 
 providing visual or audible feedback to a user of the portable electronic device, the visual or audible feedback indicating an overtemperature warning. 
 
     
     
       7. The personal electronic device of  claim 5  wherein the processing unit is configured to cause a shutdown of at least a portion of the personal electronic device in response to the monitored current or power exceeding the expected current or power draw corresponding to the operating state of the personal electronic device by a second threshold by:
 logging a shutdown event in a memory of the personal electronic device; 
 shutting down at least a portion of the personal electronic device; and 
 providing visual or audible feedback to a user of the portable electronic device, the visual or audible feedback indicating an overtemperature shutdown; and 
 cause the personal electronic device to restart in a debug mode. 
 
     
     
       8. The personal electronic device of  claim 7  wherein the visual or audible feedback indicating an overtemperature shutdown indicates that the user should return the personal electronic device for service. 
     
     
       9. A management circuit configured to monitor at least one of a current or power supplied by a battery and to compare the monitored current or power to an expected current or power draw corresponding to an operating state of a personal electronic device to detect an electrical fault. 
     
     
       10. The management circuit of  claim 9  wherein the management circuit is a power management unit. 
     
     
       11. The management circuit of  claim 9  wherein the management circuit is a battery management unit. 
     
     
       12. The management circuit of  claim 9  further configured to detect an electrical fault with a component of the personal electronic device by:
 providing a warning in response to the monitored current or power exceeding the expected current or power draw corresponding to the operating state of the personal electronic device by a first threshold; and 
 causing a shutdown of at least a portion of the personal electronic device in response to the monitored current or power exceeding the expected current or power draw corresponding to the operating state of the personal electronic device by a second threshold. 
 
     
     
       13. A method of detecting and mitigating an electrical fault in a component of a personal electronic device, the method comprising:
 monitoring, by a management circuit of the personal electronic device, at least one of a current or power supplied by a battery of the personal electronic device; 
 comparing, by the management circuit, the monitored current or power to an expected current or power draw corresponding to an operating state of the personal electronic device to detect an electrical fault with a component of the personal electronic device; 
 providing, by the management circuit, a warning in response to the monitored temperature exceeding a first threshold; and 
 causing, by the management circuit, a shutdown of at least a portion of the personal electronic device in response to the monitored temperature exceeding a second threshold. 
 
     
     
       14. The method of  claim 13  wherein the management circuit is a power management unit. 
     
     
       15. The method of  claim 13  wherein the management circuit is a battery management unit.